Too Little CO2 To End Life On Earth

It is no surprise to anyone who has studied the history of our planet and the life it harbors that CO2 levels have been falling for billions of years. Despite all the hoopla over rising CO2 levels, eventually Earth will have lost so much carbon dioxide from its atmosphere that plants and trees will suffocate, signaling an end to life as we know it. Now, a team of scientists from the California Institute of Technology, led by physicist King-Fai Li, have proposed a way to avert disaster—get rid of much of the atmosphere.

In a paper titled “Atmospheric pressure as a natural climate regulator for a terrestrial planet with a biosphere,” published in the June 1 issue of the Proceedings of the National Academy of Sciences (PNAS), Li et al., suggest that the life span of the biosphere can be extended at least 2.3 billion years, more than doubling previous estimates. Here is a description of the problem from the paper's online abstract:

Lovelock and Whitfield suggested in 1982 that, as the luminosity of the Sun increases over its life cycle, biologically enhanced silicate weathering is able to reduce the concentration of atmospheric carbon dioxide (CO2) so that the Earth's surface temperature is maintained within an inhabitable range. As this process continues, however, between 100 and 900 million years (Ma) from now the CO2 concentration will reach levels too low for C3 and C4 photosynthesis, signaling the end of the solar-powered biosphere.

There are three basic categories of plants when it comes to photosynthesis: C3, C4 and CAM. The difference between them are the ways in which CO2 is extracted from the air and the primary products of photosynthesis. In C3 plants the enzyme responsible for photosynthesis, RUBISCO, is also the enzyme involved in the uptake of CO2. Examples of C3 plans include wheat, barley, potatoes and sugar beets—most plants are of this type.

C3, C4, and CAM type plants.

C4 plants use PEP Carboxylase for uptake, which then supplies CO2 to RUBISCO for photosynthesis. CAM stands for Crassulacean Acid Metabolism. In CAM plants CO2 is stored in the form of an acid before use in photosynthesis. C4 and CAM photosynthesis are both adaptations to arid conditions and result in better water use efficiency. C4 plants include fourwing saltbush (shown in the middle picture above), corn, and many summer annual plants. CAM varieties include cactus, some orchids, bromeliads and agaves. With the end of the “solar-powered biosphere” there may be little food, but at least our distant descendants will be able to make Tequila.

It seems that solar power is not the final answer to all of our earthly problems after all, in fact it is set to become our worst nightmare. Sometime between 100 million and 1 billion years from now, Earth will become a lifeless wasteland. The cause of the biosphere's ultimate demise, however, is not certain—it is a race between CO2 depletion and the rising output from the sun. If plant-life doesn't die out soon enough, the sun is on schedule to fry the planet in about a billion years. As we mentioned in chapter 10 of The Resilient Earth, Varying Solar Radiation, all stars eventually die. Scientists think they know what the ultimate fate of our star will be.

The fate of a star when it leaves the main-sequence, after exhausting its supply of hydrogen, depends partly on its mass. Once a star's hydrogen is spent, it will start burning helium in a nuclear reaction that forms carbon and oxygen. A side effect of this change in nuclear fuel is swelling and cooling of a star's outer layers. When this happens, the star becomes a red giant.

Once helium is exhausted, a large star will burn carbon and oxygen, proceeding with successively heaver elements until iron and nickle are produced. At that point the star runs out of fuel entirely. Stars massing less than eight solar masses are not big enough to burn carbon so their careers as red giants ends when their helium supply is gone. With no ongoing thermonuclear reaction to provide heat to support it, a star will collapse.

When a star the size of the Sun runs out of fuel and collapses, the sudden contraction of matter causes one or more explosions. These explosions blow off the outer layers of the star, forming a planetary nebula. Many of the more spectacular photographs from the Hubble Space Telescope are of planetary nebulae. Over time, the matter in the nebula will disperse, leaving the burned-out remains of the star behind—a white dwarf.

But the death of the sun is not really an immediate concern, humanity will have either perished or have found a new home outside the solar system long before the sun swallows the Earth. As we said in the first chapter of The Resilient Earth:

Earth is doomed, and science tells us how our world will end. In a billion years, the Sun's output will have increased by ten percent above today's levels, causing runaway greenhouse heating and the end of life on Earth. In 5 billion years, the Sun will start to run out of hydrogen and begin to swell. In 6 billion years, the Sun will become a red giant, engulfing Mercury, Venus and Earth. Finally, in 7 billion years, the Sun will eject its outer layers and slide into retirement as a white dwarf. The Sun will spend its final days quietly cooling—a dimming ember in space. Earth, and its vibrant ecology, will have long vanished. This happens to stars and their planets all the time, it is the fate decreed by the laws of nature.

Ignoring the high probability that all life will all be incinerated by the sun in a billion years, what can be done to save Earth from CO2 depletion? As mentioned at the beginning of this article, the Cal Tech team suggests we reduce the thickness of the atmosphere, lowering air pressure to about one-sixth today's pressure at sea level. To do this we would need to develop a technology that sucks nitrogen from the air, since 78% of Earth's atmosphere consists of nitrogen. The overall affect of this thinner air would be oxygen enrichment. Of course, our distant descendants would have to alter their metabolisms, developing a physiology similar to the Sherpa people of Nepal. I doubt that the atmospheric reduction program would achieve its goals quickly, giving Earth's remaining animal life, people included, time to adapt to the new low pressure lifestyle.

Ecologist Kenneth Caldeira of the Carnegie Institution at Stanford, who has studied the implications of low carbon concentrations in the atmosphere, says the researchers have made “a persuasive case” that pressure can play an important role in the planet's long-term atmospheric composition. But he doubts that anyone knows what will happen to atmospheric pressure in the distant future. To that we can add, no one really knows what is going to happen in the near future either.

Is this the Earth of the future? Image by Jeff T Alu.

It is interesting that science has found yet another way for all life on this planet to perish that doesn't require the existence or misbehavior of mankind as its cause. According to the PNAS article, we are threatened by the loss of carbon dioxide, but in real life we are being told to get rid of it. The eventual death of the planetary biosphere due to lack of carbon dioxide tells us some things about the current CO2 induced global warming hysteria. Though carbon dioxide levels have varied widely over the 4.5 billion years of Earth's existence the trend is irrefutably downward. When taken as part of the grand sweep of Earth's history the current rise of atmospheric CO2 levels is not even noteworthy. The forces that have changed Earth's climate and atmospheric composition in the past continue to change it today and will do so until our planet dies. These natural forces are huge, titanic, beyond human comprehension and control.

In the face of such forces, mankind's power to significantly or permanently alter the environment is negligible. Those in government and regulatory agencies should think twice when they choose to call carbon dioxide a pollutant and attempt to regulate it as a toxic substance. Far from being a pollutant, CO2 is plant food and without plants there are no people. But then, politicians and alarmists are nothing if not short sighted, and human hubris knows no bounds.

Be safe, enjoy the interglacial and stay skeptical.

A student's view

So apparently I am woefully misinformed and totally ignorant of the grand scheme of things... To my knowledge our input of polutants such as CO2 has peirced, or at least thinned the ozone layer in some places while completely obscuring the sun in others. So are you all suggesting that the 'Greenhouse effect' is a bunch of bull... a sham theory meaning that mankind was never in peril of burning up its own atmosphere or fouling their own air to the point that fresh no longer exists?
Yes CO2 is important to plants, in which are like toilets that flush down what we call pollutents and excrete oxygen, but what all those that are cut down every year, doesnt that make an 'irreversible, catostrophic, permanent' impact on life as we know it? What about all the rivers and tributaries cities pollute with all sorts of waste? The BP spill? What about the rate of natural resource consumption of just agriculture alone in which is projected to seriously decline in about 50 years thus resulting in global starvation? What about the growing landfills that choke the land?
Again these are just some of my inquiries to you all based on your line of thought... please do say whether i am wrong on anypoint and why. I am profoundly puzzled to why mankind has not and can not make a fatal 'footprint' on the Earth.

Interesting Point of View

Not sure what school you went to I was taught Plants are the filters a toilet is pretty much the opposite of that, however I am not sure what your using as a toilet.

CO2 is not responsible for

CO2 is not responsible for the thinning of the ozone layer. This are CFCs which were used in refrigerators, solvents and other chemicals up to the Montreal Protocol. The banning of this substances has allowed the ozone layer to recover slowly. N2O another important ozone depleting gas is still increasing. Human's introduce more N2O than naturally through the use of fertilizer. However the banning of CFC has given us another problem as the substances we developed to replace them HFCs have high global warming potentials (thousands of times CO2). Also CO2 doesn't obscure the sun. It is transparent at visible light wavelengths. Black carbon (soot) can locally obscure the sun (e.g. Beijing). Because it is black it absorbs radiation and it has been found to be only second to CO2 in global warming effect.
There have been however several effects slowing down our effect on the atmosphere. Plants have benefit from higher CO2 such that it works as a fertilizer. They have taken up to 50% of what we emit. However plants can only do this as long as their supply of other nutrients allows them to. And it is only ~50%.
We also have emitted aerosols together with greenhouse gases. Aerosols reflect sunlight back to space, dampening the warming.
By the way greenhouse effect doesn't mean that the atmosphere will burn it will only get warmer which will affect the atmospheric circulation patterns which are driven by heat inbalances.
In general the Earth has cleaning mechanisms that will heal it once we learn to take care of it better. All this effects you mentioned are telling us we should be more responsible. You can look at "the most important video you'll ever see" in youtube. It is a lecture on exponential growth.

The Constructed Lie

First, I would like to agree with you that the pollution of our planet is a huge problem. But we must separate the subjects of environmental toxins from the subject of "greenhouse gasses".

You MUST understand that the "concern" about CO2 was a manufactured crisis created by the powerful global elites to further centralize/increase their control and wealth through CARBON TAX/TRADING. It is simply another corrupt scheme to extract wealth from the "little people" for THEIR benefit. They also needed a HUGE "crisis" upon which to construct the regulatory function of their world government. Don't believe me? Read the following quotes from powerful groups like the Club of Rome, the UN, etc.:

All is not what you think it is. I have learned that the hard way! Every sector of our society, including higher education, has been infiltrated and propagandized by very powerful and greedy individuals for VERY nefarious purposes. Think about this: The very people who are pushing the CO2 myth NEVER say ANYTHING about the true environmental issues endangering us such as: GMO's, vaccinations, fluoridated water, chemtrailing, geo-engineering, nuclear power, and on and on....

Why do you think that is? The best principle my parents ever taught me is to "follow the money"....because money and power are the ONLY things those in power care about!

Your first statement is correct

Your self assessment is accurate. You can dispel your ignorance by reading more of Dr. Hoffman's articles, found on this site.

i personally believe that we

i personally believe that we are doing just fine and don't need to be worry about that. sometimes i think we over react on certain matters. but that is my point.

Very interesting

Very interesting and alarming is that this problem really is, not so much for us but for our grandchildren and even children, because it is a problem that seriously impacts our planet, it's good quee take action on it, thanks.
post by wembaster: mesas poker

Not alarming

Don't worry about your children or grandchildren. The article cited states "As this process continues, however, between 100 and 900 million years (Ma) from now the CO2 concentration will reach levels too low for C3 and C4 photosynthesis, signaling the end of the solar-powered biosphere." That's 100 to 900 MILLION YEARS FROM NOW. Unless human lifespans increase significantly, your descendants 100 generations in the future won't be affected by this.

CO2 reduction rates

The natural process for CO2 reduction, described in this post will take 100's of millions of years.
The natural process is going to be about 1 million times slower than the current release of CO2 into the atmosphere by humans.

It is nonsense to claim that the resulting reduction of CO2 from this process has any relevance for climate change that will take place in the next century of time. Get real!

Adding rate low compared to stored carbon and almost no effect

Anonymous(21:55) says: "about 1 million times slower"

(Offtopic: Please, write a nick name!)

Exactly what do you know about geology and "1 million times slower"?

Fossil fuel is made of plants, and the amount of fossil fuel we use each year is about the amount of energy in the growing plants every year. There's a carbon cycle and only a small part of the carbon in plants are fosiled, but if only say 1/10000 of the every year growing and dead plants is fossiled the number of years to make the amount of fossil fuel we use in 100 years is 100 x 10000 = 1 million years. I'm no geologist, but I would guess that 1 million year is not an exageration.

All anthropogenic CO2 we will add into the oceans until 2100 is about 2 percent of the CO2 content of the oceans -- and there is a lot more carbon at the sea floor.

What has your comment btw to do with problem for the environment?

Also you don't say that the carbon dioxide from fossil fuel is a problem. IPCC says its lifetime in the atmosphere is 200 years, but that is right now well falsified by data from NOAA [1] and CSIRO [2]. The real number for the CO2 lifetime in the atmosphere is between 5 and 10 years, from these more than 30 studies:

Craig (1957): 7 +/- 3
Revelle & Suess (1957): 7
Arnold & Anderson (1957): 10
Siegenthaler (1989): 4-9
Craig (1958): 7 +/- 5
Bolin & Eriksson (1959): 5
Brecker (1963), recalc. by Broecker & Peng (1974): 8
Craig (1963): 5-15
Keeling (1973b): 7
Brecker (1974): 9.2
Oeschger et al. (1975): 6-9
Keeling (1979): 7.53
Peng et al. (1979): 7.6 (5.5-9.4)
Siegenthaler et al. (1980): 7.5
Lal & Suess (1983): 3-25
Siegenthaler (1983): 7.9-10.6
Kratz et al. (1983): 6.7

Based on Suess Effect
Ferguson (1958): 2 (1-8)
Bacastow & Keeling (1973): 6.3-7.0

Based on bomb carbon-14
Bien & Suess (1967): >10
Münnich & Roether (1967): 5.4
Nydal (1968): 5-10
Young & Fairhall (1968): 4-6
Rafter & O’Brien (1970): 12
Machta (1972): 2
Broecker et al. (1980a): 6.2-8.8
Stuiver (1980): 6.8
Quay & Stuiver (1980): 7.5
Delibrias (1980): 6.0
Druffel & Suess (1983): 12.5
Siegenthaler (1983): 6.99-7.54

Based on radon-222
Brecker & Peng (1974): 8
Peng et al. (1979): 7.8-13.2
Peng et al. (1983): 8.4

Based on solubility data
Murray (1992): 5.4

Based on carbon-13/carbon-12 mass balance
Segalstad (1992): 5.4

Details here:

If our CO2 change a balance, which isn't likely -- we'll year 2100 get the content of 51 atmosphere's CO2 in the ocean instead of 50 atmosphere's CO2 -- we may got a higer CO2 concentration which would be good for us, but I don't think we'll be that lucky. The CO2 concentration will remain low, only about 2 percent higher than otherwise.


It is Very real indeed

Yes, the processes described in this post take place over hundreds of millions of years, and that is part of the point. Proponents of anthropogenic global warming throw around terms like "catastrophic" and "irreversible" with little respect for historical accuracy. Humanity needs to get a grip—we are nowhere near powerful enough to have truly irreversible, catastrophic impact on Earth. We might inconvenience ourselves but then who told mankind to build all those cities on the coast?

Sea levels have been 20 m higher and 120 m lower within the last 20,000 years. That should tell us something about the world we live in. Even if we were all dirt farmers, spending our days staring at the ass end of an ox, the oceans may rise or fall enough to turn us into refugees. New York City used to be 400 miles inland—of course, it also used to be under a mile of ice—the point being, all this furor about human caused climate change is total bullshit.

The climate is going to change with or without mankind's puny contributions to global warming. This is as real as it gets, you need to get your head out of the sand and gain some appreciation for how nature actually works.

Is several times higher CO2 emission negative for ocean life?

I think it's important to not be alarmistic about anything which is within reasonable limits, and I don't want an alarmistic standard answer. Q: What would happen if we start to emit say 5 times more CO2 than we're emit now?

I'm not so worried about the atmosphere or the climate. I think the saturated greenhouse effect is a plausible and correct theory, and that we in general have an atmosphere strongly dominated by negative feedbacks, which in recent years is proved by lots of empirical data.

My concern is about how much CO2 the oceans can take in 100 years of time. I'm not worried about the rate we're burn fossil fuel now. We will add one atmosphere's natural CO2 content in the ocean within 100 years, and that is a change a bit larger than the variation in CO2 concentration and oceans content between the ice ages and interglaciers the last millions of years. What will the chemical effect be if we add 10 percent of the oceans content of CO2 within 100 years? Is it innocent or somewhat harmful? I don't think this obvious.

It's a hypothetical question, because (A) we may in reality not increase CO2 emissions more than 50-100 percent until 2050 (a period of time when things will get more energy efficient, world population will peak at 8.5 billion, and most people will have western standard) and after that probably substatially lower the emissions, maybe back to current levels (or lower). Also I assume (B) that there will be an abundance of fossil fuel, which exclude the peak oil theory (which I think is a bit of sloppy science, "deceptive statistics" etc) and makes it possible to increase the coal and oil production to a 5 times higher level.

I also assume that CCS (Carbon Capture and Sequestration) will not be very successful.

So, if we increase the fossil consumption 5 times and thus in 100 years add CO2 corresponding to 10 percent of the oceans CO2 content, what will then happen to the ocean's pH-level, and to the life in the oceans? Is this in CO2 emissions corresponding to the supervolcanoes every million of years or so, or is it a lower CO2 impact -- or a lower environmental impact -- than those are? Does anyone has chemical facts etc in the brain memory?

I think a doubling of the fossil fuel emissions is possible when this crazy climate buzz is over, but should we begin to be cautious then about one further doubling? Is that really within reasonable limits?

We emit 5 times more in next 40-90 years

Doug+the anomymous reply one day later:
You state 'Humanity needs to get a grip..' And you go on to say we've lived with 20 m higher and 120 m lower over 20,000 years. (Homo sapiens has also lived through one and a half ice ages and 1.9 (?) interglacers, so he's resilient.) I agree 100%.
But now here comes a reply that is highly believable. His concern is not the atmos or climate, but the oceans. And we have time to learn about this over the next 40 to 90 years. And certainly adjust to your 20 meters ocean rise, say in 500 years..!(?)
I have BS and MS degrees in ChE so I just beginning to understand this 'field.' I have been an oil manager and appreciate the idea of a lot more coal, oil and natgas use. Along with the idea that CO2 is great for plants. So it would really be great if you two could somehow collaberate to put together a fuller story on those three - the atmos, the climate, and the oceans.
If you cannot find #2, do it yourself.
Thanks...Vern Cornell

Vern's comment

Doug.....I've read this blog several times since March,2011.... It is totally interesting. But I await your "study" of
the comment just before mine, just above.
THAT will be totally interesting squaired!..... Vern Cornell